Second-generation mobile communication refers to the transmission and reception of voice in a digital form, such as CDMA, GSM, and the likes. GPRS, which is more advanced than the GSM, has been proposed, and the GPRS is a technology to provide a packet switched data service based upon the GSM system. The GSM/GPRS is a system based upon TDMA.
Third-generation mobile communication refers to the transmission and reception of video and data as well as voice, and 3GPP (Third Generation Partnership Project) developed a mobile communication system (IMT-2000) technology, and adopted WCDMA as a radio access technology (hereinafter, referred to as “RAT”). By combining both of such an IMT-200 technology and a radio access technology (RAT), e.g., WCDMA, it is called UMTS (Universal Mobile Telecommunication System) in Europe. Furthermore, the term UTRAN is an abbreviation of UMTS Terrestrial Radio Access Network.
On the other hand, it is expected in the third-generation mobile communication that data traffic will rapidly increase in the future, and a standardization work is being carried out to make an evolutionary network having a higher bandwidth (Long-Term Evolution Network: LTE).
In the LTE, the term E-UTRAN (Evolved-UTRAN) is used, and OFDMA (Orthogonal Frequency Division Multiple Access) is used as a radio access technology (RAT) in the E-UTRAN.
On the other hand, as various kinds of radio access technologies (RAT) exist as described above, there is a problem in the interoperability between the 2nd-generation GSM/GPRS and the 3rd-generation UMTS. Moreover, a problem also arises in the interoperability between radio access technologies when a new radio access technology (RAT) appears, such as E-UTRAN.
In order to solve the problem, operators provide a roaming service between radio access technologies. It is because the existing equipment is also reusable from a standpoint of those operators. For this purpose, terminals can support multi-RATs. The terminal may take a measurement on neighboring cells of a different RAT (for instance, measured power, RSRP (Reference Signal Received Power), SNR, etc.), and move to a cell of the different RAT. Through this, the terminal can maintain service quality while receiving better signals.
Owing to this, terminals can continually receive a mobile voice and data service.
In other words, when the user of the terminal moves into the UTRAN/E-UTRAN in the state of voice communication in a GERAN (GSM/EDGE Radio Access Network) network, a handover/cell reselection takes place automatically between two networks during a voice call and data session.
FIG. 1 is an exemplary view illustrating a handover between GERAN/E-UTRAN networks.
As illustrated in FIG. 1, a handover/cell reselection is performed when a terminal 10 making a call within the coverage of a base station (BTS) 21 in a GERAN moves into the coverage of a base station (eNode B) 22 in a E-UTRAN.
For such a handover or cell reselection, a serving cell provides information on a neighbor cell, for instance, an E-UTRAN cell, and the terminal performs measurement and/or reports its own measurement result on neighbor cells (e.g., measured power, SNR, etc.) to the network.
Hereinafter, it will be described with reference to the accompanying drawing.
FIG. 2 is a flowchart illustrating a method for receiving information on a neighbor cell according to the related art.
Referring to FIG. 2, a base station 20 of each RAT transmits an information message on a neighbor cell, e.g., Neighboring Cell Information, to the terminal 10 (S11). At this time, the information message on a neighbor cell is transmitted through a broadcast channel or a dedicated channel.
Then, the terminal 10 takes a measurement on SNR, reception power, etc. for the neighbor cells, and may transmit a message for reporting a result of the measurement, e.g., Measurement Report message, to the base station 20 (S12).
Furthermore, the terminal 10 generates a Neighbour cell list and based upon the result of the measurement, and performs a cell reselection or a reports measurement result in accordance with the generated cell list.
However, in the related art, the base station 20 of each RAT transmits an information message on a neighbor cell, e.g., Neighboring Cell Information, in a different format from one another, and thereby it has a problem that the terminal 10 is unable to acquire accurate information on a neighbor cell.
Moreover, an information message on a neighbor cell in the related art, e.g., Neighboring Cell Information, includes unnecessary information in each terminal 10, and thereby network resources are used wastefully.
In addition, an information message on a neighbor cell in the related art, e.g., Neighboring Cell Information, includes duplicated information, thereby it has a problem that network resources are used wastefully.